Following Monday night's 1-0 win over Arsenal, United boss Sir Alex Ferguson revealed the popular South Korean will miss seven matches once he flies back home after the Boxing Day clash with Sunderland.
If the Koreans are knocked out of the Cup the three-week tournament in Qatar early, Park will be back sooner.
Bright spark: Park Ji-Sung celebrates after bagging the winner against Arsenal in the clash at Old Trafford
But as one of the favourites to lift the trophy that seems unlikely and means Ferguson will badly miss the services of Park.
'I have mixed feelings about the Asian Cup,' said Park. 'At the moment I am playing with confidence, so I do feel a bit strange about going.
'But I am always happy to join my national team as well. Even without me Manchester United have enough players to keep winning, so I will concentrate on the national team and then focus on Manchester United.'
Park's first-half header against Arsenal was the fourth time he has scored against them - considering he 29-year-old's overall tally since he moved from PSV Eindhoven in 2005 is just 22.
The latest effort was amongst the most spectacular as he had to act fast to change his body position as Nani's right-wing cross bounced down off Gael Clichy.
'It was a strange goal,' he said. 'The ball changed direction so I had to move suddenly.
'I thought it was going to hit the post. But finally it went in and I was able to celebrate. It was a good goal for me and the team.'
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